I skimmed through the video and something I noticed was that the Earth could be seen in reflections of the astronaut's helmet and particularly shiny parts on the station. If that was done in a pool (which it would have to be if it was fake considering how long it was) it would be nearly impossible to get convincing reflections of the Earth which is supposedly done with green screen. It would require camera tracking for all reflective objects and using a virtual reflector object which reflects the Earth and a virtual station identical to the real one, floating wires and all. Any obstructions to the reflective object would have to be virtual objects which mask the reflection object which is nearly impossible unless you went through the video frame by frame, which is not very practical for a video of this length. My prediction is that a single skilled animator would take 6 months to a year of working many hours every day to make reflections like what we see and if I factor in the time it takes to create the necessary rigs and assets it would take at least 2 years.
Another thing to note is that if that video was filmed in a pool even the clearest water looks like this:
In the video you could distinctly see solar panels and stuff far enough away that in even the clearest water they should look like they are a bit blue, yet this is not the case. Here is a photo of an astronaut training pool:
Note the blueness which is not there in the real ISS photos.
Here is another interesting proof that they are really in space: refraction. Water is denser then air, so if you look at an astronaut's head in a space suit under water then their head would look small like this:
However, empty space is (obviously) less dense then air which will make their head appear bigger like this:
I honestly can't think of any way that this effect could be faked with CGI. Wait, but if the ISS videos are taken in a vacuum then they must be in zero G and the only way to get zero G for that long is to orbit the Earth because no zero G plane can do that, especially with a payload as big as the ISS. This must mean that space travel is real and the Earth sure does look round in those space photos.